Prevalence and determinants of wasting among under‐5 Egyptian children: Application of quantile regression

Abstract Wasting is one of the symptoms of malnutrition that has been connected to the deaths of malnourished children. This study was intended to explain the effect of socio‐demographic and economic factors on under‐5 wasting by evaluating their conditional effect across the distribution of weight‐for‐height Z (WHZ) scores using the quantile regression (QR) model. The weighted sample which included 13,680 children under 5 years was taken from the countrywide Egyptian DHS 2014 survey. The results depicted that about 2% of Egyptian children were severely wasted, with the prevalence of wasting being around 8%. It was discovered that across the WHZ distribution, the child's features, maternal characteristics, father's education, and social factors had significant but varied contributions in explaining the wasting status of under‐5 children. It was revealed that female children had a significant weight advantage, notably 0.21 standard deviation (SD) higher weight at the 95th quantile over their male counterparts. The WHZ score was also found to be significantly positively associated with both age and household's wealth status at the lower and upper tails of the WHZ distribution, respectively. Moreover, in comparison with children whose mothers were underweight, those whose mothers were normal or overweight had higher WHZ scores, with a 1.45 SD increase in WHZ scores at the 95th quantile for mothers who were normal weights. Furthermore, the children who were breastfed, whose mothers received antenatal care (ANC) services, and/or who had educated parents had an advantage in terms of WHZ scores than their counterparts. In addition, the children with higher birth order and/or who resided in urban areas had weight disadvantages compared to their counterparts. Therefore, in order to improve children's nutritional status and achieve the Sustainable Development Goals (SDGs) by 2030, the government and public–private owner organizations must work together at the community level focusing on vulnerable groups.


| INTRODUC TI ON
Undernourished children have weakened immunity and impaired cognitive function, which leads to their poor health outcomes, loss of future productivity, and low academic performance (Anato, 2022;WHO & UNICEF, 2009). Consequently, undernutrition is responsible for almost half (45%) of all deaths in under-5 children worldwide (Anato, 2022;FAO et al., 2017). Wasting or acute malnutrition refers to a child's thinness due to a lack of nutritional intake and/or illness (Karlsson et al., 2022;Motbainor & Taye, 2019). It is one of the most severe manifestations of the global public health concern termed as undernutrition in the developing countries (Motbainor & Taye, 2019). There are many gravely detrimental impacts of wasting on children's health, with the highest risk of mortality (Black et al., 2013;Ghosh-Jerath et al., 2017;Harding et al., 2018;Tickell et al., 2017). Severe wasting is one of the leading hazards to child survival, resulting in one in five deaths of under-5 children worldwide, killing more than 1 million children every year (UNICEF, 2022).
Annually, 8 million deaths are anticipated to be caused by wasting, with severe wasting responsible for 60% of these deaths in low-and middle-income countries (LMICs) (Anato, 2022;Black et al., 2013).
There were 45.4 million wasted children worldwide under the age of 5 in 2020, with 13.6 million of those being severely wasted (Anato, 2022;UNICEF et al., 2020). Africa has the second highest prevalence of wasting (27%) in the world (Anato, 2022). In Egypt, the prevalence of wasting in children under the age of 5 is 9.5% which is more than 1.5 times the average rate of wasting (6.0%) for the African region (Global Nutrition Report, 2022). In addition, the socioeconomic effects of COVID-19 might also contribute to an increase in the prevalence of wasting (Headey et al., 2020). One of the "United Nation's (UN) Sustainable Development Goals (SDGs)" to be achieved by 2030 is "Zero Hunger" with the target of "end all forms of malnutrition by 2030" (United Nations, 2015). However, Egypt is indeed far from reaching its goal of reducing childhood wasting (Global Nutrition Report, 2022). Consequently, the existing policies and intervention programs against wasting should be redesigned focusing on the really vulnerable groups in order to lessen the burden of wasting in Egypt.
The socio-demographic and economic profiles of all the wasted children and their families are not the same. Therefore, earlier studies explored that many child's features-including sex, age, birth order, low birth weight, inadequate breast feeding, infectious diseases, vaccination, insufficient energy and micronutrient intake, and inappropriate complementary feeding practices; parental characteristics-such as education, low nutritional knowledge and awareness, mother's age and body mass index (BMI), ANC visits during pregnancy period, and birth spacing; as well as some social factors-including types of living area, wealth status, and food availability; environmental factors and many more have significant contribution in explaining the wasting status of children under the age of 5 (Ali et al., 2017;Anato, 2022;Biadgilign et al., 2016;Black et al., 2013;Harding et al., 2018;Karlsson et al.,  Motbainor & Taye, 2019; Mukabutera et al., 2016;Ntenda & Chuang, 2018;Rahman et al., 2008;Rahman & Chowdhury, 2007;Tigga & Sen, 2016;Vollmer et al., 2017).
However, few studies have been conducted on wasting in Egypt.
Abdel Wahed et al. (2017) conducted a cross-sectional study based on school-based survey data and identified the significant determinants of malnutrition through stepwise logistic regression analysis in Fayoum Governorate, Egypt (Abdel Wahed et al., 2017). In a separate study by Khatab (2010), the author discussed the associated factors of malnutrition by employing geoadditive Gaussian and latent variable models in Egypt (Khatab, 2010). Using both simple and multiple logistic regression models, El-Sayed et al. (2001) determined the contributing factors to malnutrition among preschool children in Alexandria, Egypt (El-Sayed et al., 2001).
Nevertheless, the quantile regression (QR) approach can be utilized to describe the diverse association through the distinct percentiles of the conditional distribution of the WHZ score (Sharaf et al., 2019), and the QR outcomes might be helpful in designing appropriate policy and intervention measures, especially in the presence of outliers and nonnormality in the dataset (Olsen et al., 2012;Yeh et al., 2009). Several researchers applied the QR model to examine the core socio-demographic factors of child nutritional status but all of those studies have been conducted in the out context of Egypt (Aturupane et al., 2011;Borooah, 2005;Fenske et al., 2013;S Hossain et al., 2022;Rahman & Hossain, 2022;Sharaf et al., 2019).
The focus of this study was to use the QR approach to quantify the heterogeneous effects of socio-demographic and economic fac-

| Statistical methods
To determine the findings of this study, descriptive statistics, percent distribution, and the Chi-square were used. The boxplot was employed to detect the presence of outliers and the estimates of mean and variance were influenced by outliers (Hossain, 2016(Hossain, , 2017; however, in this circumstance, QR provided the robust results. Then, the quantile function can be presented in the following way

Background characteristics Percent
Weight-for-height (wasted) in % p-Value of chi-square Z-score <−3 SD Z-score <−2 SD The parametric form of the quantile regression model can be stated as where, 0 , 1 , … , k are the coefficients that may differ on . The

| RE SULTS
The boxplot presented in Figure 1 depicted that there were outliers in the WHZ scores of the under-5 children in Egypt. This was the motivation working behind using QR regression analysis in this study.  Figure 2).
In the bivariate analysis, the identified significant determinants were incorporated in the QR analysis. It was observed that the Pseudo R 2 increased from lower to upper quantile levels, indicating that the effect of the related factors on WHZ score increased from lower to upper quantiles. Notably, the considered factors were found to be less important to explain the variation in the WHZ score.
It was discovered that the QR estimates of the sex of the child at all F I G U R E 2 Prevalence of wasting among children region in Egypt chosen percentile levels (10%, 25%, 50%, 75%, and 95%) were found to be significant. Furthermore, in comparison with the child's age group of less than or equal to 6 months, all other age groups' coefficients were negative and statistically significant at the majority of the percentiles, indicating a negative influence on the WHZ score.
Additionally, children with higher birth order had larger WHZ score than those who were the first children of their parents. Duration of breastfeeding and mother's age were also found to have no significant effect on the WHZ score. Moreover, the QR estimates demonstrated a positive association between the mother's BMI and WHZ, even though the coefficients had a negative sign at the lowest percentile but switched sign at higher percentiles with strong significance and higher magnitude ( Table 2). urban areas were scored worse on the WHZ indicator than those who lived in rural areas. As well, a ridiculous scenario was also demonstrated by the significant coefficients against ANC visits. In addition, the wealth index had a statistically significant positive association with WHZ at some percentiles; interestingly, children who came from the middle, richer, and richest families had a lower WHZ than children who came from the poorest families at the 10th percentile ( Table 2). The heterogeneous effects along with 95% confidence interval of some selected determinants throughout the entire conditional WHZ distribution are illustrated in Figure 3.

| DISCUSS ION
This study was aimed to assess the conditional heterogeneous ef-

TA B L E 2 (Continued)
made a similar conclusion with 26% higher odds of wasting in male children than their female counterpart and postulated biological and social factors for explaining the sex difference in wasting (Thurstans et al., 2020). If the excessive demand for nutrients due to a greater biologically programmed trajectory in male children is not met adequately, they will experience deficit earlier and much more than female children which may partially describe the link between sex and wasting (WHO Multicentre Growth Reference Study Group & de Onis, 2006). The age of a child was found to be strongly connected to wasting in children below 5 years of age, with the WHZ score decreased as the child's age increased.
Our findings are also supported by previous research (Darteh et al., 2017;Islam et al., 2020). This could be due to the fact that children are more vulnerable to infections throughout their first year of life. The children having higher birth order had a weight disadvantage than the first child of the parent. The plausible explanation, for this reason, maybe the parents are probably more careful of their first child.
Parental education had a significant influence on the various points of the conditional WHZ distribution of under-5 children, this result is consistent with the findings from previous studies (El et al., 2009;Semba et al., 2008;Sharaf et al., 2019;Sharaf & Rashad, 2016). Nutritional status has long been connected to socioeconomic status, which is often defined by income and education level. The amount spent on nutritionally balanced foods is influenced by one's income. Moreover, educational attainment influences nutritional knowledge and awareness regarding health, environment, childcare, food habits, physical activity, and so on (Sharaf et al., 2019). The relationship between a father's education and WHZ score could be explained by the fact that educated fathers have educated spouses, leading to improved care practices for their children. Therefore, nutrition and health-related education should be integrated into the education system in Egypt.
Except at the 10th quantile, the children of mothers with normal or overweight had an advantage in terms of weight than those of mothers with underweight. In several earlier research, maternal BMI was also identified as the most predictive variable of children's WHZ score (Ali et al., 2017;Khan et al., 2019;Li et al., 2020;Tigga & Sen, 2016 (Islam et al., 2020;Sharaf et al., 2019). The prevalence of wasting is varied by region. Probably, geographic disparities, such as road and railway networks, products availability and costs, nutritional diversity and customs, conflicts, and land scarcity, could explain these within-country variances (Rahman & Hossain, 2022;Sharaf et al., 2019;Sharaf & Rashad, 2016).

| S TRENG TH S AND LIMITATI ON S
The strength of this study was the novelty of the work and considering the country representative EDHS-2014 data. This was a cross-sectional study; therefore, the causal inference was not possible. Furthermore, there may be spatial and temporal variation exist in the prevalence of wasting but the authors did not consider it here.

| CON CLUS IONS
This study discovered that sex, age, birth order of the children, duration of breastfeeding, mother's BMI, parental education, place of residence, number of ANC visits during pregnancy, and household's wealth status had varied effect (in magnitude and direction) throughout the conditional distribution of WHZ score of the children under the age of 5 in Egypt. According to the findings of this study, it is recommended to update the current undernutrition remedial policies and strategies as well as develop some need-based intervention measures focusing on the vulnerable populations in order to lessen the burden of wasting. The authors are confident that the outcomes of this paper would help policymakers in accelerating the achievement of the SDG-2 in Egypt.

ACK N OWLED G EM ENTS
The authors are grateful to ICF International, Rockville, Maryland, USA, for providing the DHS data sets for this analysis. We are also grateful to the well-wishers and their peers to motivate us for doing this research. Last but not least, the authors would like to sincerely thank the reviewer, the Editor, and Academic Editor, for their valuable comments and suggestions, which have been used to improve the quality of the manuscript.

CO N FLI C T O F I NTE R E S T
The authors have declared that no competing interests exist.

DATA AVA I L A B I L I T Y S TAT E M E N T
The access link of dataset is http://dhspr ogram.com/data/avail abledatas ets.cfm.

E TH I C A L A PPROVA L
This study was based on an existing public domain survey dataset that is freely available in online after removing all identifier information of the respondents through a registration process. The survey was approved by the Ethics Committee of the ICF Macro at Calverton in the USA and by the Ethics Committee in Egypt.